Circuit interrupter



June 22, 1948. w E BERKEY 2,443,650

CIRCUIT' INTERRUPTER Filed Sept. 27, 1944 2 Sheets-Sheet 1 j@ j. Egg1725.3. 17324.

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' lNvENToR Wil/iam E 5er/hy.

BY 9J q 2 ATTORNEY Patented June 22, 1948 UNIT ED STATES GfFF'lC-El yCIR'CIT IN TERRUPTER. William Ef, Berkey, Forest Hills; Pa., assignortoWestinghouse Electric Corporation, VEast Pittsburgh, Pal, a corporationof Pennsylvania Application September 27, 1944, Serial No. `555,967

7 Claims. 1

'IEhisv invention yrelates to circuit 'interruptera in general, fand,-more particularly, to arc extinguishing structures therefor.

AA general object is 'to provide an improved circ'nt'interrupter inwhich an arc is established and rotated. Preferably during the rotationthereof-the arc yis forced against Vbaiiie means disposed-directlyinthe-path of the rotating arc.

Another object is to provide an improved circuitinterrupterof therotating arc type Vin which f thefcontact structure has anfimproved'constructions Further objects and advantages will readilybecomeapparent from a reading of Athefollovvingspeciiication taken inconjunction with the drawings, in which:

Figures 1 4. theoretically illustrate the principles involved in myinvention;

Fig. 5 is a sectional view taken along the line V--V of Fig. 6;

Fig. 6'is a vertical sectional View taken substantially along the lineVI--V of Fig. 5, the parts .being shown in the closed circuit position;

Figs. 7 and 8 illustrate modied types of baflle platevconstruetions;

(Fig. 9 is an enlarged plan View of a modified type otcontactconstruction;

Fig. 10 is a sectional View taken along the line X-X of Fig. 9;

Fig. l1 is a sectional View taken along vthe line XI-XI of Fig. 12; and

Fig. 12 is another modiiied type of contact construction.

Referring to the drawings and, more particularly, to Figs. 1 and 2thereof, it will be noted that an arc I is established by means notshown between the cooperable contacts 2, 3, the arc extending through a.hole 4 provided in a baile plate 5 composed of a suitable gas evolvinginaterial such as horn fiber or boric acid. The @baffle platey 5 ismoved toward the left as indicated by the arrow 5a by suitable means notshown so that the edge E oi the hole 4 engages the arc Iv causing thelatter to assume a bowed shape as shown in Fig. 2. The arc I causesgases to 'be evolved from the plate 5 which react upon the arc forcingit in the direction of the arrows 1 of Fig. 2. These forces caused bythe gas evolving from the plate 5 do not necessarily have aldi-rectionwhich is perpendicular to the axial length of the arc but may have arandom direction as they act against the are I.

Thus the constructions shown in Figs. 1 and 2'illustrate the forcesacting upon the arc which result 'from physically movingvthe Ybaiileplate s5 composed of a suitable gas evolving material laterally VVsothat one .edge ofthe hole 4engages the'arcl.

The construction shown in Figs. Band Liz-illus.- trate lan arrangementwhereby thearc vI .moved between the cooperablecontacts 2, 3 .by meansoffa transverse magnetic field: 'passing :perpendicular-ly into theplaner of the paper. Consequently, the arc movesin a direction that. isnot only perpendicular to its `length but alsolinffa direction which isperpendicular to the magnetic neld.- The forces exerted bythe magneticfield onthe larc -I lare designated by the arrows Band are always/in'adirection perpendicularly .to the axial' lengthl ci' the arc I and:uniformiyy distibutedalong its length. .As the arc lI is moved towardthe right by the action of the magnetic eld,-fthe-fbaflle plate 5invthis instance .remaining stationary,zthe are I will` again engage-theedge '6 of thefplate 5, which is composed -of a suitable gas evolvingmaterial.

The-arc Iagain'assumes a bowed-shape: as shown in Fig- 4 but it`vvvillnbe observed that in this. instance the= arrows` 8 sti-lll reactuponthe arc Iv in afdirection Vperpendicularly -toits axial length andtend '-to intimately force the arcI against thebaflie plate 5 to-causeagreater evolutionfof` gas lthan was the casein Fig. 2. results becauseof the uniform distributienet forces along the length of ithe arc. Thearrows 1 again indicate the forces-exertedy by the gas evolved from` theplate 5. asa result of the Iin timate engagement of the arc I thereon.

Consequently, from the examination of Figs. 1 4, it will beobserved-thatthe construction shown in Fig.. Lis far superior tothe constructionshown in Fig. 2where only the lbaiile plate 5 is physically moved. Inother Words by utilizing a magnetic eld the engagement between the arc Iand the plate 5 is more effective and there correspondingly -vresultsagreater evolution ofgas from ythe bafe plate 5. The greater evolutionof. gasl consequently more readily effects the extinction of the arc I.

Thel use oi a ydirect-current eld results in an additional advantage.The reaction forces with a direct-current magnetic field to4 move thearcremain nite andlarger in magnitude as compared with an A.C. magnetic eldas the arc current yapproaches zero; If an alternating-currentl magneticiield is used` then the reaction forces on the arc decrease faster asthe current approaches Izero :because both the field and current aredecreasing.

Figs. 5 and 6 show an embodiment of any incurrent source for energizingthe eld coils 9.

I0, the radial magnetic eld which is thus set up between the magneticcore I3 and the pole plate I4 and indicated by the arrows I5 of Fig. 5does not diminish in strength as a function of time.

the movable bridging contact I6 from the ringshaped contact I'I an arc I(Fig. 5) is established and rotated around the ring-shaped contacts I1,I8.

Disposed between the ring-shaped contacts I1, I8 are bale means of gasevolving material generallydesignated by the reference numeral I9 anddisposed directly in the path of the rotating arc I which is initiallydrawn through a hole 4 of the baille means I9., In this instance thebaille means I9 comprises a g inch thick fiber plate having 1%; inchdiameter holes 4 provided therein adjacent its periphery as more clearlyshown in Fig. 5.

It will be observed that in the closed circuit position, as shown inFig. 6, the movable bridging contact I6 extends through one of the holes4 provided in the insulating plate 29 of annular configuration andcomposed of gas evolving material.

-The terminal connections to the interrupter as shown more clearly inFig. 6 comprise a terminal strip 2| connected by a screw 22 to the upperring-shaped contact I8.` The-other terminal of the interrupter comprisesa terminal strip 23 electrically connected by a screw 24 to the lower`ring-shaped Contact I'I.` The current passing-between the contacts I8,II may be either direct current or alternating current. If alternatingcurrent is employed, and the'eld coils 9, I0 are energized from an4alternating-current source, preferably the iield coils would beserially connected with the contacts I-l, I8 to an alterhating-currentsource. 1 e

The contact structure may be secured in place by an insulating sleeve 25which surrounds an annularly shaped block of insulating material 26, thelatter lhaving an annular groove 21 into which is xed the lowerring-shaped contact I'I. The annular `plate 29 is held in position bytwo insulating sleeves 28, 29 which surround the core I3. An insulatingcap 30 may be provided having apertures 3l formed therein to permit anescape of the gases formed during the rotation of the arc I. The eldcoils 9, I0 surround cores 32, 33 respectively formed of suitablemagnetic material, such as iron, whichV extend between the pole platesI4, 34. If desired the contact structure may be biased toward the opencircuit position by means of a compression spring 35 interposed betweenthe cap 3l!l and a flange 36 integrally formed with the movable bridgingcontact I6. A bracket 37 secured by a screw 38 to the cap 30 may beemployed to guide the movement of the bridging contact I6. Suitableactuating means not shown may be employed to eiect longitudinal movement-of the bridging contact I6.

Consequently, upon the upward movement of` contacts I8,` I'I, severaltimes, jumping from hole The arc I may jump from hole to hole as itiotates around the ring-shaped contacts I8, I'I each time striking anedge 6 of the holes 4 as shown in Fig. 4 to cause a considerableevolution of gas. The extent of rotation depends upon the force F (Fig.5) which acts on the rotating arc I, and the force F in turn dependsupon the magnitude of the current being interrupted and the radialmagnetic eld strength.

Actually the arc I may circle the ring-shaped to hole during therotation thereof.

' In place of the gas evolving nber plate 20, insulating plates 39 or 40as shown in Figs. 7 and 8 may be employed.

` The fiber plate 39 in Fig. 7 has provided there- .y in threearcuately-shaped slots 4I and the fiber plate 49 has a singlearcuately-shaped slot 4I.

Preferably, each of the ring-shaped contacts I8, Il' has either aconstruction as shown in Fig. 9 or a construction as shown in Fig. 12.-The modified construction shown in Fig. 9 comprises a ring-shapedcontact 42 having a hole 43 provided therein through which the bridgingcontact I9 extends. The contact 42 has a plurality of concentricallydisposed annular grooves 44 provided therein. The depth of the grooves44 was 1A; inch and the width of the grooves 44 was 12 inch, asillustrated in the cross section of Fig. 10. Such a construction gaveexcellent results.

Another contact construction which gave very good results is that shownin Figs. 11 and 12 wherein a plurality of radially disposed grooves 45were provided in the modied contact construction 46. The depth of theradial grooves 45 was 1/8 inch and the spacing between adjacentlydisposed grooves 45 was substantially 1A; inch.

Therabove two contact constructions facilitate arc rotation inasmuch asthe arc rotates by jumping from point to point in its rotative movement.A portion of the arc length near the terminal end of the arc bows downin the direction of arc travel, and the above two constructions takeadvantage of this phenomena by facilitating the jumping of the arc froma previous point of arc termination to a point adjacent to which thebowed portion of the arc neared the contact. This jumping phenomenacontinues dur-ing arc rotation. y

Another important consequence of the reaction force F exerted by themagnetic radial eld on the arc I during the rotation thereof is toproduce acceleration of gas and thereby produce an air blast whichcarries away the arc gases. The field will move the arc terminals as faras the holes in the barrier plate 20 will permit, such motion increasingthe arc voltage together With the alc length. As mentioned previously,restriking between successive holes 4 may result, thus causing the arc Ito jump from hole to hole as it rotates around the contacts Il, I 8. v

From the foregoing description it will be apparent that I have providedan improved circuit interrupter of the rotating arc type in which thearc is drawn through a hole in suitable baiile structure and rotated,the arc during the rotation thereof striking against the side of thehole to produce a considerable evolution of gas. `I have illustratedimproved contact constructions and have shown three different types ofbaffle structures which may be employed. By utilizing the particularconstruction disclosed in conjunction with rotative arc movement.contact burning is minimized, turbulence is in creased, and considerablearc travel is possible with a structure of minimum overall size.

Although I have shown and described specific structures, it is to beclearly understood that the same were merely for the purpose ofillustration and that changes and modifications may readily be madetherein by those skilled in the art without departing from the spiritand scope of the appended claims.

I claim as my invention:

l. In a c-ircuit interrupter, a pair of cooperable ring-shaped contacts,means for establishing an arc between the ring-shaped contacts, meansfor establishing a radial magnetic field for causing rotation 0f the arcaround the ring-shaped contacts, and at least one of the contacts havinga plurality of concentrically disposed annular grooves provided thereon.

2. In a circuit interrupter, a pair of cooperable ring-shaped contacts,means for establishing an arc between the ring-shaped contacts, meansfor establishing a radial magnetic field for causing rotation of the arcaround the ring-shaped contacts, and at least one of the contacts havinga plurality of radially disposed grooves provided thereon.

3. In a circuit interrupter, a pair of separated endless ring-shapedcontacts immersed in air, an insulating plate disposed between thecontacts yand having a plurality of spaced holes disposed therein, meansfor establishing an arc between the separated contacts through one ofthe holes, means providing a radial magnetic eld to cause rotation ofthe arc around the endless ringshaped contacts, and said holes in theinsulating plate being of substantially uniform size and spacedsubstantially equidistant about a circular path so that as the arcrotates around the contacts it jumps from hole to hole and extinguishingaction at the edges of the holes is immediately brought to bear upon therotating arc.

4. In a circuit interrupter, a pair of separated endless ring-shapedcontacts immersed in air, an insulating plate disposed between thecontacts and having a plurality of spaced holes disposed therein, meansfor establishing an arc between the separated contacts through one ofthe holes, means providing la radial magnetic field to cause rotation ofthe arc around the endless ringshap'ed contacts, and said holes in theplate being disposed symmetrically about a circular path so that as thearc rotates around the contacts it jumps from hole to hole andextinguishing action at the edges of the holes is immediately brought tobear upon the rotating arc.

5. In a circuit interrupter, a pair of separated endless ring-shapedcontacts immersed in air, an insulating plate disposed between thecontacts and having a plurality of spaced holes disposed therein, meansfor establishing an arc between the separated contacts through one ofthe holes, means providing a radial magnetic eld to cause rotation ofthe arc around lthe endless ringshaped contacts, the holes in theinsulating plate being disposed in a circular path and relativelyclosely together so that as the arc rota-tes around the contacts itjumps from hole to hole and there being a plurality of holes in the rsthalf turn around the ring-shaped contacts so that eX tinguishing actionat the edges of the holes is immediately brought to bear upon therotating arc.

6. In a circuit interrupter, a pair of cooperable ring-shaped contacts,means for establishing an arc between the ring-shaped contacts, meansfor establishing a radial magnetic field for causing rotation of the arcaround the ring-shaped contacts, -at least one of the contacts having aplurality of concentrically disposed annular grooves provided thereon,and an insulating plate dis- ;posed between the ring-shaped contactswith a plurality of spaced holes therethrough so that the arc jumps fromhole to hole as it rotates around the contacts.

7. In a circuit interrupter, a pair of cooperable ring-shaped contacts,means for establishing an arc between the ring-shaped contacts, meansfor establishing `a radial magnetic field for causing rotation of thearc around the ring-shaped contacts, at least one of the contacts havingla plurality of radially disposed grooves provided thereon, and aninsulating plate disposed between the ring-shaped contacts with aplurality of spaced holes therethrough so that the arc jumps from holeto hole as it rotates around the contacts.

WILLIAM E. BERKEY.

REFERENCES CITED The following references are oi record in the le ofthis patent:

UNITED STATES PATENES Number Name Date 1,039,305 Hewlett Sept. 24, 19122,095,301 Wilcox Oct. 12, 1937 2,112,033 Lingal et al Mar. 22, 19382,138,391 Van Sickle Nov. 29, 1938

